In MS SQL Server, it is well documented that the type of the primary key can have a dramatic effect on performance. Using narrower types and sequential values significantly improves insert performance when using SQL Server, which is why using integers instead of guids for surrogate keys tends to make sense.
However, I cannot find any references to the same discussion for Oracle. Someone asked me to look at a schema for them that uses varchar2(32)'s for all of the primary keys, which seems much wider than needed. Does this matter in Oracle?
Bonus points for anyone who can refer me to a good blog like Kimbery Tripp's but in Oracle world.